Around three-quarters of people with ME report problems with their eyes and vision – but you wouldn’t know it from the mainstream scientific literature.
COLIN Barton, Chair of the Sussex ME Society looks at the evidence.
There is very little formal published evidence that these symptoms exist, despite the fact they greatly affect quality of life and can be easily measured. This means that there is no solid, evidence based scientific data to back up patients’ reports of their disabling visual disturbances. For that reason, ME Research UK has awarded a grant to the University of Leicester to identify and quantify vision-related problems in the disease.
To date, the Leicester group have published two robust scientific papers. In the first, they showed that ME patients were less able than healthy people to focus selectively on a specific target while ignoring other irrelevant information, and that patients were slower when it came to moving their attention to a target, slower at scanning, and more easily affected by ‘distractors’.
Their second paper revealed that eye movement dysfunction was a prominent feature, and that patients performed worse than healthy people in tasks that required quick and accurate movements of the eyes.
The researchers have now published a third, descriptive report describing the visual symptoms (problems with focusing or attention, and loss of depth perception) experienced by their ME patients. All patients included in the study reported having no history of eye disease, yet 92% had some degree of sensitivity to bright lights; 88% were unable to focus vision and/or attention; and 6% experienced eye pain. Each of these symptoms was severe or very severe in more than 30% of the patients, and there was a close relationship between severity and frequency of symptoms.
The researchers’ aim in publishing their report in the British Journal of Ophthalmology is to increase awareness among healthcare professionals, including ophthalmologists, of the importance of problems with vision in ME. As they point out, their report “adds to an emerging body of evidence that vision related symptoms represent a significant clinical feature,” that might be useful for diagnosis.
Colin Barton – Sussex ME Society